The ARP table maps IP addresses to MAC addresses on a local network. Which statement correctly describes this mapping?

• A. IP address to OSI layer 3 address
• B. IP address to MAC address
• C. Domain name to IP address
• D. Port number to service

Answer: (B)

ARP translates an IP address into the MAC address used on the local network. The ARP table (cache) records these IP-to-MAC mappings so a host can place the correct destination MAC in the Ethernet frame when delivering an IP packet on the same LAN. If the MAC isn’t known, a host broadcasts an ARP request asking who has that IP, and the responding device provides its MAC, updating the ARP cache. This is specifically about converting an IP address to a hardware (MAC) address to enable on‑the‑wire delivery. The other options describe different mappings: domain names to IP addresses (DNS) and port numbers to services; the ARP table is not about those.